The goals of the proposed project will be to further develop, biologically validate, employ, and model biological response indicator devices for gauging environmental stressors (BRIDGES). The biological response indicator devices are complementary passive sampling devices (PSD) that bridge environmental exposure and biological response/effect. Because bioavailability processes are embedded in human and ecosystem health risk frameworks, the development of complementary bio-analytical tools that quantitate bioavailability processes is important. Bio-analytical tools that have been rigorously biologically validated using a robust aquatic developmental model system are needed to biologically anchor these analytical approaches. Specifically, we will further develop the BRIDGES tool to assess fate and bioavailability of PAHs (polycyclic aromatic hydrocarbons) in sediments and overlying waters within Superfund, contaminated, urban, and undeveloped field sites and in controlled laboratory studies. Under Specific Aim 1 we will further develop environmental exposure bio-analytical measurement technologies capable of quantitatively sequestering bioavailable contaminant concentrations. Under Specific Aim 2 we will utilize the zebrafish developmental model to test the relative potency of PSD extracts from current Superfund, urban, and undeveloped sites. Under Specific Aim 3 we will develop discriminatory chemical/physical fractions and constructions of PSD extracts from signatory biological responses in the zebrafish model. Develop discriminatory pattern recognition and multivariate regression assessments of co-varying components in PSD extracts and signatory biological responses. Develop a predictive link between biological response/effect and environmental exposures measured by BRIDGES. Under Specific Aim 4 we will develop discriminatory pattern recognition and multivariate regression assessments of co-varying components in PSD extracts and contaminant source type. The role of environmental exposure and the development of complex human and aquatic health effects require innovative interdisciplinary approaches. We propose to combine two independently developed model systems to further develop, correlate, and validate exposure and response. This interface between environmental exposure and aquatic/human health risk is needed to reliably bridge quantification of exposure and environmental health.